Not showing full amount of RAM

I've got an oldish Packard Bell that I want to get more speed out of. It was 128mb RAM and I bought 2 sticks of 256 (the maximum I can for the mobo) from ebay and put them in. The computer now shows me as having 256 mb RAM.
I took 1 stick out to see if it's only reading 1, and it showed as 128 again. I swapped them over and it still said 128.
I used Everest and Sisoft Sandra and they both showed the same. It's as if it's only reading 128 from either stick.
I also tried 1 stick of 512 and it was the same, showing 128.

Any ideas?

 

Make sure you have the latest BIOS installed.

 

old board .... maybe you have to change setting in your bios check if you have something about RAM in bios or your board do not accept more then
256 megs of ram ???

 

I've checked the maximum. I ran a Crucial scan and it said 2X256 Mb maximum, also same from the modo manufacturers website.

I've looked in BIOS and couldn't see anything referring to RAM THERE.

Do I download latest BIOS from the website and run that? Is that risky at all?

 

It's not risky if you do it correctly.

Make sure you read the instructions very well.

 

Sounds like the memory modules are simply incompatible with the motherboard (quite common). Take them back to your supplier and swap them with a different model / brand and try again.

If that doesn't work, make sure your motherboard supports dual sided (2 bank) modules as this would also cause the same problem (if the memory you've purchased is double sided).

 

You may be getting near the problem then. The banks have 2 sides with the little chip type things (don't know the technical term) on them. The 128 mb I took out only had them down one side. I take it that means I should get single-sided? Is that how it works then, only recognises the anount of memory on one side?

 

Well, it could still be a memory incompatibility but it's worth investigating.

Does your system motherboard manual have any description on memory configuration?

This may give u an insight into exactly how many banks are available.

If it says there are only 2 banks (normally 0 & 1) then YES, single sided is required. If it says there are 4 banks (0,1,2 & 3), then it's a simple case of getting a different brand / model memory module (single or double sided) and trying that.

Sorry about the long reply - hopefully it'll be of some help

 

I didn't get a manual with my PC. Unfortunately, I bought it a few years ago from one of the large computer retailers, before I knew better .

According to the manufacturers website it has 2 banks. I can see that when I take the side off.

How come it only accepts single sided if 2 banks, but double if 4?

Sorry to ask so many questions but I'm keen to learn.

 

All motherboards have a limit on the number of memory banks available. This is normally between 4 - 12, depending on the make & model of the board.

These are subsequently allocated to memory slots on the motherboard via the boards memory controller. Normally, modern boards will allocate 2 banks per slot. Therefore, on a board with 3 slots (e.g. Abit's NF7 series), a total of 6 banks is spread across the 3 slots (i.e. 2 / slot). However, some manufacturers (e.g. Gigabyte) will sometimes only make 6 banks available on a board which has 4 slots (confused? u will be!). This can cause MAJOR difficulty for any user wanting to populate all the slots. This is where the motherboards manual is crucial to a trouble free life . The manual should explain which slots can be used with either double or single sided memory to make up any desired memory size (256MB - 3GB).

Some of the "cheaper" manufacturers (compaq is obviously one of them) will only make 2 banks availble, if that board has 2 slots, it stands a chance that each slot will only have 1 bank associated with it.

So...

...I would suggest u take back your knew memory and swap it for single sided.

Still glad u asked?

 

Thanks for the reply. It helps me understand a bit better.

I've found the spec for my mobo, and it actually supports double-sided

Have a look here

What does this bit mean "Supports a maximum memory size of 512 MB (128-bit technology) or 256 MB (64-bit technology) for SDRAM "?

I can't actually take back what I bought as it's from ebay. Probably serves me right for trying to save money as Crucial would supply the correct one. Probably have to sell it on ebay and buy some more.

 

Oops - I knew there was a reason I don't use that site!

and sry about quoting Compaq; I should have put "Packard Bell" instead - ho hum

But Compaq are just as bad